Polymers and copolymers of methyl acrylamido-glycolate methyl ether, commercially available under the trade name MAGME.RTM. 100 Multi-functional Monomer, and polymers and copolymers related to the MAGME.RTM. 100 monomer are described in U.S. Pat. Nos. 4,656,308; 4,778,728; 4,454,301; 4,521,563; 4,808,660; 4,689,264; 4,522,973; 4,743,498; 4,880,880; 4,554,337; 4,737,544; 3,422,139; European Patent Application Nos. 302,588 and 224,736; and Federal Republic of Germany Pat. No. 3,613,082. U.S. Pat. No. 4,454,301 in particular describes the use of acid or transesterification catalyst-cured systems. Sulfonic acids and tin salts are mentioned therein as examples of cure catalysts.
Other MAGME.RTM. copolymers having moderate (Mw about 30,000) molecular weights are disclosed in the proceedings of the ACS Division of Polymeric Materials Science and Engineering, Volume 55, page 315, 1986. Use of MAGME copolymers in coatings is described in the Proceedings of the Water-Borne Higher-Solids Coatings Sympoisum, Volume 16, page 505, 1989.
Polymers and copolymers of methyl acrylamidoglycolate methyl ether and related systems described above are high molecular weight polymers, and in some cases, such as in the case of latexes, emulsions, and dispersions, they are very high molecular weight polymers as described below.
The average molecular weights of polymers of methyl acrylamidoglycolate methyl ether exemplified in U.S. Pat. No. 4,454,301 are disclosed to be in the 54,000 to 70,000 range; polymers exemplified in U.S. Pat. No. 4,880,880 are in the 46,000 to 73,000 molecular weight range; polymers of unetherified methyl acrylamidoglycolate disclosed in European Patent Appl. No. 224,736 are said to range between about 500 to about 1,000,000, although higher molecular weights are said to be usable; in general, the latexes, the emulsions, and the dispersions comprise even higher molecular weight polymers.
This invention relates to very low molecular weight acrylamidoglycolate polymers and copolymers said very low molecular weight polymers having molecular weights of 10,000 or less. The use of said low molecular weight polymers and copolymers as crosslinkers in coil coatings is described in the copending applications submitted concurrently herewith entitled "Organotin Curable Composition and Coating Method", U.S. application Ser. No. 07/786,496 now abandoned; and "Acid Curable Composition and Method", U.S. application Ser. No. 07,786,442 now abandoned. The MAGME.RTM. based crosslinkers of the invention are typically combined with polyfunctional resins and are subsequently cured to form crosslinked coatings or articles. One of the important advantages of MAGME.RTM. based systems over the widely used amine-formaldehyde crosslinkers such as melamine based crosslinkers is that the MAGME.RTM. based crosslinkers do not produce formaldehyde by-product on cure.